top light switch only works moved over to the right

One of my other moms has a 94 plymouth voyager. the light in the ceiling does not come on when the door is opened but will come on when the slide switch on the dash board is moved all
the way to the right.
Is this a problem with the switch or the bulb?
Would a squirt of contact cleaner be likely to do any good?
I have tried moving the switch back anf forth again and again but it doesn't help at all.
Thanks for any help.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
Add image file
Upload is a website by car enthusiasts for car enthusiasts. It is not affiliated with any of the car or spare part manufacturers or car dealers discussed here. All logos and trade names are the property of their respective owners.